A single procedure for preparing the cytoplasmic and mitochondrial forms of malate dehydrogenase and aspartate aminotransferase as well as Beta-hydroxyacyl CoA dehydrogenase from pig heart has been devised. The sequence of the cytoplasmic malate dehydrogenase has been partially fitted to the electron density map determined for this protein by L.J. Banaszak and coworkers. The mitochondrial malate dehydrogenase obtained from this procedure is homogeneous and free of more acidic subforms, which appear to be generated during preparative manipulations. Characterization of these subforms has been initiated. Amino acid sequence analysis of the major component is in progress. Tryptic peptides have been isolated and are presently being characterized. The amino terminal sequence has been determined in the Sequencer. Beta- Hydroxyacyl CoA dehydrogenase has been fully characterized. Many of the properties of this protein are similar to those of mitochondrial malate dehydrogenase, suggesting that these proteins have evolved from a common precursor gene. This conclusion is supported by limited but significant immunological cross reactivity. The preparation of D-3-phosphoglycerate dehydrogenase from pig liver has been initiated. Sequence analysis of carp muscle calcium-binding proteins A1 and C have been essentially completed. Structural studies on components A2 and D are in progress. These data suggest there are two families for these proteins with related genetic origins. The sequence of E. coli alkaline phosphatase is completed except for the C-terminal portion of fragment I. A crab collagenase with specificities toward both tryptic and chymotryptic activities has been isolated and characterized. Sequence studies have been initiated. The amino acid sequence of an 82 residue fragment from E. coli biotin carboxyl carrier protein has been initiated. About 2/3 of the structure has been elucidated.